class Solution {
public:
    int wiggleMaxLength(vector<int>& nums)
    {
        int ret = 1;
        int n = nums.size();
        vector<int> f(n, 1), g(n, 1);
        for (int i = 1; i < n; i++)
        {
            for (int j = i - 1; j >= 0; j--)
            {
                if (nums[i] > nums[j])f[i] = max(g[j] + 1, f[i]);
                else if (nums[i] < nums[j])g[i] = max(f[j] + 1, g[i]);
            }
            ret = max(ret, max(f[i], g[i]));
        }
        return ret;

    }
};